Hanheld printing apparatus

ABSTRACT

Provided is a printing apparatus including: a holding unit configured to be held by a user to move the printing apparatus; a printing unit configured to print an image onto a print medium according to a movement of the printing apparatus; a guide unit configured to guide the movement of the printing apparatus; a first detection unit configured to detect a relative moving amount between the printing apparatus and the print medium; a second detection unit provided at a position different from a position of the first detection unit; and a displacement unit configured to displace the first detection unit from a state where the first detection unit and the second detection unit are both in contact with the print medium into a state where the first detection unit is separated from the print medium.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a handheld printing apparatus forperforming printing by having an operator manually scan its body.

Description of the Related Art

A handheld printing apparatus for performing printing by having a usermanually scan its body has been known. Japanese Patent Laid-open No.2019-162795 (hereinafter Document 1) discloses a handheld printingapparatus having a plurality of sensors that measure the amount ofmovement of the printing apparatus relative to a print medium. Document1 also discloses that the plurality of sensors detect the moving amountof the printing apparatus during a scan for printing.

In a case where a plurality of sensors constantly contact a print mediumto detect the moving amount of a printing apparatus as in the techniquedisclosed in Document 1, there is a possibility that the sensors arerubbed against a printed area of the print medium. In this case, if anink yet to be fixed is remaining on the printed area, there is apossibility that the rubbing of the sensors causes scraping anddetachment of the ink, transfer of the ink onto another area, therebycausing soiling, and so on, which deteriorate the printing quality.

SUMMARY OF THE INVENTION

A printing apparatus according to one aspect of the present invention isa printing apparatus including: a holding unit configured to be held bya user to move the printing apparatus; a printing unit configured toprint an image onto a print medium according to a movement of theprinting apparatus; a guide unit configured to guide the movement of theprinting apparatus; a first detection unit configured to detect arelative moving amount between the printing apparatus and the printmedium; a second detection unit provided at a position different from aposition of the first detection unit; and a displacement unit configuredto displace the first detection unit from a state where the firstdetection unit and the second detection unit are both in contact withthe print medium into a state where the first detection unit isseparated from the print medium.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are perspective views illustrating a manually scannedhandheld printing apparatus;

FIGS. 2A to 2D are views illustrating a printing operation of theprinting apparatus on a print medium in a step-by-step manner;

FIG. 3 is a block diagram illustrating a configuration of a control unitin the printing apparatus;

FIGS. 4A to 4H are views illustrating a line break mechanism in theprinting apparatus along the flow of a line break operation;

FIGS. 5A to 5D are views illustrating a positional relationship betweena printed area and the printing apparatus, and operating states ofsensors;

FIGS. 6A and 6B are views illustrating a downstream position detectionsensor and components around it;

FIGS. 7A and 7C are views illustrating an upstream position detectionsensor and components around it; and

FIG. 8 is a diagram describing an example of calculating a change inangle which occurred in a movement by a line break operation.

DESCRIPTION OF THE EMBODIMENTS (First Embodiment)

A first embodiment of the present invention will be described below withreference to drawings.

Note that the term “print” herein is not limited to formation ofinformation with a meaning such as characters or a figure, and includesformation of information with a meaning and also information without ameaning. Moreover, the term is not limited by whether what is to be“printed” is elicited so as to be visually perceptible to humans, andrepresents a wide range of meanings such as formation of an image, adesign, a pattern, or the like on a print medium and processing a printmedium.

Also, the term “ink” (also referred to as “liquid”) is to be widelyinterpreted as with the definitions of “print” mentioned above. Thus,the term represents a liquid to be used to form an image, a design, apattern, or the like or process a print medium by being applied to aprint medium, or to process an ink (e.g., solidification orinsolubilization of a colorant in an ink to be applied to a printmedium).

“Print medium” is mainly a medium such as a paper sheet or note, but isnot particularly limited to these as long as it is a medium on whichprinting can be performed by attaching an ink. “Print medium” may be anymaterial as long as it accepts an ink, such as fabric, plastic film,sheet metal, glass, ceramic, wood, or leather.

FIGS. 1A and 1B are perspective views illustrating a manually scannedhandheld printing apparatus (hereinafter also referred to simply as“printing apparatus”) 1 in the present embodiment. FIG. 1A is a viewillustrating the top side of the manually scanned handheld printingapparatus 1, while FIG. 1B is a view illustrating the bottom side of themanually scanned the handheld printing apparatus 1. The printingapparatus 1 includes an upper unit 3 mainly containing a control unit'scomponents, a lower unit 2 including a print head 4 and guide rollers10, and a line break handle 5 to be operated by an operator in a case ofperforming a line break operation. The print head 4 performs printing byejecting an ink onto a print medium with movement of the printingapparatus 1.

A plurality of guide rollers 10 are provided. In the present embodiment,these are a paired right guide roller 10 a and left guide roller 10 bwhich guide movement of the printing apparatus 1 in ±X directions (firstdirection) while pressing a print medium P during a printing operation.

The lower unit 2 is provided with a downstream position detection sensor11 and an upstream position detection sensor 12 with the print head 4therebetween. The downstream position detection sensor 11 and theupstream position detection sensor 12 are provided to be capable ofcontacting the print medium. Relative to the print head 4, thedownstream position detection sensor 11 is situated on a side in thetraveling direction in a line break operation after printing a singleline (i.e., in the moving direction for line break), and detects therelative moving amount between the printing apparatus 1 and the printmedium. The upstream position detection sensor 12 is situated on theopposite side of the print head 4 in the traveling direction in a linebreak operation, and detects the moving amount of the printing apparatusbody. In the present embodiment, as will be described later, a linebreak operation of the printing apparatus 1 is an operation of moving ina +Y direction (second direction). Thus, the +Y side will be referred toas the downstream side in the traveling direction for line break (newline side), while the −Y side will be referred to as the upstream sidein the moving direction for line break (previous line side). Thedownstream position detection sensor 11 includes a downstream positiondetection sensor case 11 a, sensor case sliders 11 b, a sensor lens 11c, and a Y-direction sensor support shaft 11 d (FIGS. 6A and 6B). Theupstream position detection sensor 12 includes an upstream positiondetection sensor case 12 a, sensor case sliders 12 b, a sensor lens 12c, and a Y-direction sensor support shaft 12 d (FIGS. 7A and 7B). Thelower unit 2 is further provided with line break legs 13. The line breaklegs 13 are members that separate the guide rollers 10 from the printmedium and move the printing apparatus body during a line breakoperation, and include a pair of right line break legs 13 a and a pairof left line break legs 13 b. During a line break operation, the tworight line break legs 13 a and the two left line break legs 13 b contactthe printing surface of the print medium.

The right guide roller 10 a and the left guide roller 10 b are eachformed as an integrated component with one shaft 10 c and two rollersfixed to this shaft 10 c. The two rollers are provided coaxially witheach other. The shafts 10 c of the right guide roller 10 a and the leftguide roller 10 b are provided substantially parallel to each other, andare supported by the lower unit case 14 so as to allow the shafts 10 cto turn while reducing their backlashes in the thrust direction. Eachroller's cylindrical surface that contacts the print medium P ispreferably subjected to a process such as sticking fine abrasive grainsto increase the coefficient of friction with the print medium P, and thetwo rollers are preferably given substantially the same diameter toachieve good straightness of travel. For the straightness of travel, itis also preferable to support the right guide roller 10 a and the leftguide roller 10 b in parallel to each other. During movement on theprint medium P, configurations as above enable the guide rollers 10 topassively roll without slipping, and also improve the straightness oftravel of the printing apparatus 1.

These mechanisms serve as a base of the lower unit 2 and housed in thelower unit case 14, in which the print head 4, the guide rollers 10, andso on are disposed.

FIGS. 2A to 2D are views illustrating a printing operation of theprinting apparatus 1 on the print medium P in a step-by-step manner. InFIGS. 2A to 2D, areas PA represent printed areas where images areprinted. A case of printing a first single line from the left side ofthe print medium P toward its right side will be described below. Notethat it is also possible to perform the first printing from the rightside of the print medium P toward its left side.

When starting the printing, the printing apparatus is positioned at anupper left portion of the print medium P, as illustrated in FIG. 2A. Inthis state, of the components of the printing apparatus 1, the fourrollers 10 a and 10 b of the guide rollers 10 and the sensor casesliders 11 b, which are part of the downstream position detection sensor11, are in contact with the print medium P, whereas the upstreamposition detection sensor 12 is not in contact with the print medium P.The upstream position detection sensor 12 is not in contact with theprint medium P during the printing operation in order to avoid rubbingthe printed area after the later-described line break operation isperformed. Specifically, as the printing apparatus 1 performs a linebreak operation, the position of the printed area and the contactposition of the upstream position detection sensor 12 on the printmedium P move relative to each other in the moving direction for linebreak. Thus, in the course of repeating line break operations, thecontact position of the upstream position detection sensor 12 on theprint medium P may overlap the printed area in the moving direction forline break in some cases. If the printing apparatus 1 is scanned forprinting in this state, the sensor case sliders 12 b of the upstreamposition detection sensor 12 will be rubbed against the printed area. Aninkjet print head is used as the print head 4 in the present embodiment.If an ink yet to be fixed is remaining on the printed area, there is apossibility that the sensor case sliders 12 b sliding over the inkscrape and detach the ink and transfer the ink onto another area,thereby causing soiling. Thus, in the present embodiment, the upstreamposition detection sensor 12 is controlled to be separated from (out ofcontact with) the print medium P during printing operations. Note that,as illustrated in FIG. 1B, the rollers 10 a and 10 b of the guiderollers 10 on the upstream side in the moving direction for line break(−Y side) are positioned closer to the print head 4 than the sensor casesliders 12 b are. Nonetheless, since the rollers 10 a and 10 b makerotational motions on the print medium P, moving them on the printedarea does not deteriorate the printing quality, as compared to thesliding movement of the sensor case sliders 12 b.

Thereafter, in FIG. 2B, the operator places a hand on the printingapparatus 1 and moves the printing apparatus 1 in the moving directionfor printing (the direction of the arrow DX). When the printingapparatus 1 starts moving, the downstream position detection sensor 11detects the moving amount.

In the present embodiment, while the printing apparatus 1 is moved inthe moving direction for printing by the operator's operation, thedownstream position detection sensor 11 is used to detect the movingamount. Also, while the printing apparatus 1 is moved in a line breakdirection by a line break operation by the later-described line breakmechanism, the downstream position detection sensor 11 and the upstreamposition detection sensor 12 are both used to detect the moving amount.The detected moving amount is more accurate with a detection resultbased on a plurality of detection sensors moving amount than with adetection result obtained from a single detection sensor. For thisreason, the printing apparatus 1 in the present embodiment includes aplurality of detection sensors. As a rule, it is preferable to use aplurality of detection sensors to detect the moving amount. However, inthe present embodiment, as mentioned above, the upstream positiondetection sensor 12 is configured to be separated from the print mediumP in the case of moving the printing apparatus 1 in the moving directionfor printing, in order to prevent the upstream position detection sensor12 from being rubbed against the printed area. Specifically, thedistance between the upstream position detection sensor 12 and the printmedium P is a first distance during execution of line break operations.Moreover, the distance between the upstream position detection sensor 12and the print medium P is a second distance longer than the firstdistance in periods other than during execution of line breakoperations.

An example of the detection of the moving amount by the two detectionsensors is described below. The downstream position detection sensor 11and the upstream position detection sensor 12 optically readcharacteristics of the surface of the print medium P, detect the movingamount from the movement start position, and integrate this movingamount to thereby calculate the current position of the printingapparatus 1. In the present embodiment, sensors of types capable ofaccurately detecting moving amount are used, and the working distancebetween the sensors and the print medium P needs to be 2.4 mm with thedistance tolerance range kept within ±0.3 mm. A printing operation isperformed by detecting the relative moving amount between the printingapparatus 1 and the print medium P with sensors as above and ejectingthe ink from the print head 4 according to the moving amount of theprinting apparatus 1. Note that the detection method of the downstreamposition detection sensor 11 and the upstream position detection sensor12 is not limited to the above method, and may be any method as long asit can detect the relative positions of the printing apparatus 1 and theprint medium P.

Now, a configuration of a control unit 16 in the printing apparatus 1will be described. FIG. 3 is a block diagram illustrating aconfiguration of the control unit 16 in the printing apparatus 1. Thecontrol unit 16 includes a CPU 200, a RAM 201, a ROM 202, a head driver203, an external interface 205, and a wireless interface 206. Moreover,the control unit 16 is connected to an operation panel 204, the printhead 4, the upstream position detection sensor 12, the downstreamposition detection sensor 11, a battery 207, and a line break leg sensor208. The CPU 200 is responsible for performing data processing,obtaining sensor information, and controlling the driving of the printhead. The RAM 201 is responsible for temporarily storing programs andimage data to be printed and the like. The ROM 202 stores programs andvarious setting values. The head driver 203 is responsible for controlfor ejecting the ink from the nozzles in the print head 4.

The operation panel 204 is provided in the printing apparatus 1 andincludes various switches, a display unit such as an LED display, abuzzer, and so on. The external interface 205 is responsible for dataexchange with an external control apparatus and the like. The wirelessinterface 206 wirelessly controls the printing apparatus 1 in place ofthe external interface 205. The battery 207 is used to drive theprinting apparatus 1 in a cordless manner. The line break leg sensor 208detects the operation of the line break legs 13 to be described later.The ink ejection of the print head 4 is controlled by these componentsof the control unit 16. Specifically, before the start of a printingoperation, at least print data necessary for printing a single line isreceived via the wireless interface 206 or the external interface 205,and this print data is stored in the RAM 201. After various printsettings are determined and the printing operation becomes ready to bestarted, the operator is notified via the operation panel 204 that theprinting operation can be started.

The print head 4 employs an inkjet method by which it ejects the inkfrom a plurality of minute nozzles arranged substantially straight in adirection crossing the moving direction for printing. Specifically, theprint head 4 has a nozzle array being a plurality of nozzles arrangedside by side, and the direction in which the nozzle array is arrangedcorresponds to the moving direction for line break. An image is formedby reading data out of the RAM 201 according to the result of the movingamount detection by the downstream position detection sensor 11 andcausing the CPU 200 to determine the timing and the data to be printedat the corresponding position, and ejecting the ink from the print head4 as appropriate. At this time, the printing apparatus 1 is manuallyscanned by the operator. The moving speed is therefore not guaranteed tobe constant, and the speed is expected to vary. Control is performedsuch that the image will be printed as indicated by the original data onthe print medium P even with such speed variation. By continuouslyperforming this process, the operation of printing a single line iscompleted. After the completion of the single-line printing operation,the operator looks at the image or is notified of the completion of thesingle-line printing operation via the operation panel 204, and stopsthe scanning operation in the moving direction for printing DX.

In FIG. 2C, a line break operation is performed by the operator'soperation. The line break operation is an operation performed for thepurpose of applying an effect equivalent to a so-called line feedoperation involving conveying a sheet by a predetermined distance aftera single-line printing operation of the carriage in a general serialscan-type printer. Specifically, the line break operation is anoperation of moving the print head 4 in the moving direction for linebreak (the direction of the arrow DY), which is substantially orthogonalto the moving direction for printing (the direction of the arrow DX), toa position from which to perform the next single-line printing operationaccording to the position, on the print medium P, of a printed area PA1completed by the single-line printing operation.

While details of the line break operation will be described later, theoperator's operation involves moving the line break handle 5 in a leveroperating direction for line break (the direction of the arrow ML). Inconjunction with the line break operation triggered by this operator'soperation, the line break legs 13 act so as to move the printingapparatus 1 a predetermined distance in the moving direction for linebreak (the direction of the arrow DY). Note that the printing apparatus1 includes a mechanism that brings not only the downstream positiondetection sensor 11 but also the upstream position detection sensor 12into contact with the print medium P during a line break movement. Themoving amount of the printing apparatus 1 may vary, and the printingapparatus 1 may rotate in the plane of the print medium P (in thedirection of the arrow R in FIG. 2C) before or after the line breakmovement. In this case, by detecting the state of the line breakmovement of the printing apparatus 1 with the plurality of positiondetection sensors, it is possible to detect the amounts of the variationand the rotation. Note that the upstream position detection sensor 12 isconfigured to be separated from the print medium P again when the linebreak movement is finished. The line break operation is now completed.

Thereafter, in FIG. 2D, a printing operation is performed for the secondline. The printing operation of the second line is prepared by preparingimage data by a process similar to that for the printing operation ofthe first line and, if the moving amount varied during the line breakoperation, correcting the variation. The operator performs a basicoperation similar to that for the first line. Here, by preparing printdata during the line break operation, the printing operation will bebasically ready to be performed after the line break operation. In thisway, the operator can immediately start the second scan. Since thescanning direction for the second line is the reverse of the scanningdirection for the first line, the operator moves the printing apparatus1 in the direction of the arrow −DX.

The image of the second line is formed in a similar manner to the scanfor the first line by detecting the moving amount with the downstreamposition detection sensor 11 and ejecting the ink from the print head 4according to the position. By performing appropriate correction, imagescan be formed in a unified manner in the printed area PA1 of the firstline and a printed area PA2 of the second line with almost nomisalignment. Note that description of the method of the correction isomitted since it is not the subject matter of the present embodiment. Ifnecessary, the operator continuously performs a printing operation in asimilar manner for the third line, the fourth line, and so on tocomplete forming the desired image.

FIGS. 4A to 4H are views illustrating the line break mechanism in theprinting apparatus 1 along the flow of a line break operation. The linebreak mechanism in the printing apparatus 1 includes a line break lever50, a line break mechanism drive gear train 51, a drive gear train resetlever 52, a drive gear train reset sub lever 53, and a drive gear trainreset cam 54. The line break lever 50 operates in conjunction with theline break handle 5. The line break mechanism drive gear train 51 isdriven in response to the operation of the line break lever 50, andcauses the line break legs 13 to operate. The line break legs 13 arerotationally moved in the clockwise direction in FIGS. 4A to 4H by theline break mechanism drive gear train 51. When the line break legs 13come into contact with the print medium P, the line break legs 13 serveas fixed base points on the print medium P, about which the printingapparatus 1 rotationally moves in the clockwise direction in FIGS. 4A to4H.

The drive gear train reset lever 52 brings the line break mechanismdrive gear train 51 back to its initial state. The drive gear trainreset sub lever 53 operates in the last half of the operation ofbringing the line break mechanism drive gear train 51 back to itsinitial state. The drive gear train reset cam 54 receives force from thedrive gear train reset lever 52 and the drive gear train reset sub lever53. The drive gear train reset cam 54, which is on the line breakmechanism drive gear train 51, is provided integrally with one of thegears of the line break mechanism drive gear train 51, and rotates inthe counterclockwise direction in FIGS. 4A to 4H in response to theoperation on the line break lever 50. Also, gears coupled to both sidesof both sides of a gear integrally provided to the drive gear trainreset cam 54 rotate in the clockwise direction in FIGS. 4A to 4H inresponse to the operation of the line break lever 50. The line breaklegs 13 make the clockwise rotational movement in synchronization withthis rotation.

FIG. 4A illustrates a normal standby state and a printing operationstate before entering a line break operation. The line break handle 5 isstopped at its initial position in a state of being biased by a springnot illustrated. The guide rollers 10 are in contact with the printmedium P and supported by bearings not illustrated which are provided inthe lower unit case 14. Hence, the height to the printing apparatus 1 isdetermined by the guide rollers 10. The downstream position detectionsensor 11 is constantly pressed in such a direction as to contact theprint medium P, thereby being ready to measure the moving amount. Theupstream position detection sensor 12 has retracted to a retractedposition in conjunction with the line break mechanism drive gear train51, thereby not being in contact with the print medium P. The line breaklegs 13 are in a standby state at their initial positions inside theprinting apparatus 1, being not in contact with the print medium P.

FIG. 4B illustrates a state where the operator starts pulling the linebreak handle 5 in the +Y direction in FIG. 4B, thereby starting a linebreak operation. In response to the start of the line break operation,firstly, a lock member (arm drive lever A 63 in FIG. 7A) which hasretracted the upstream position detection sensor 12 moves in a −Zdirection. As a result, the upstream position detection sensor 12becomes movable in the ±Z directions (up-down direction), and alsopressed by a pressing spring not illustrated in the —Z direction intocontact with the print medium P. Thereafter, in FIG. 4C, the operatormoves the line break handle 5 farther in the +Y direction. This causesthe line break mechanism drive gear train 51 to act so as to move theline break legs 13 in the −Z direction into contact with the printmedium P.

Next, in FIG. 4D, the line break handle 5 is moved farther in the +Ydirection by the operator's operation. As a result, the line break legs13 project farther than the guide rollers 10 in the −Z direction. Thiscauses the printing apparatus 1 to start moving in the +Z direction. Theline break legs 13 themselves make a transitional movement having arotational locus inside the printing apparatus 1 in conjunction withgears of the line break mechanism drive gear train 51. Since the tips ofthe line break legs 13, which are made of a slip resistance material,are in contact with the print medium P, the body of the printingapparatus 1 conversely starts moving in the +Z direction with atransitional movement having a rotational locus.

Specifically, the body of the printing apparatus 1 moves in thedirection of the arrow A in FIG. 4D. FIG. 4D illustrates a state wherethe printing apparatus 1 has reached a half of the moving amount for theline break operation. This is a state where the printing apparatus 1 hasmoved a distance L1 in the moving direction for line break (+Ydirection) from its position before the start of the line break (thewhite triangle mark in FIG. 4D). It can be observed that the height fromthe print medium P to the body of the printing apparatus 1 was H1 at thepoint of FIG. 4C but the height to the body of the printing apparatus 1has increased to H2 in FIG. 4D. As the body of the printing apparatus 1gets separated from the print medium P, the guide rollers 10 getseparated from the print medium P as well. This enables the printingapparatus 1 to move forward in a direction other than the movingdirection in the printing operation. As the line break mechanism drivegear train 51 further rotates from the state of FIG. 4D, the printingapparatus 1 starts moving in the −Z direction. During this time too, theupstream position detection sensor 12 keeps receiving a pressing forcefrom the pressing spring. Thus, not only the downstream positiondetection sensor 11 but also the upstream position detection sensor 12remains in contact with the print medium P.

Next, in FIG. 4E, the line break handle 5 is moved farther in the +Ydirection by the operator's operation and reaches a predeterminedposition. As a result, the guide rollers 10 contact the print medium P,and the line break legs 13 are contained in the printing apparatus 1.With the guide rollers 10 contacting the print medium P, the guiderollers 10 act such that the printing apparatus 1 stops moving in theline break direction (+Y direction). The printing apparatus 1 has nowcompleted moving a moving amount L2 determined in advance by theconfiguration of the line break mechanism drive gear train 51.Thereafter, in FIG. 4F, the line break handle 5 is returned to itsinitial position illustrated in FIG. 4A by the action of the spring notillustrated. Note that the above does not apply if the operator keepsholding the line break handle 5. Incidentally, the line break lever 50and the line break mechanism drive gear train 51 are coupled via aone-way clutch not illustrated. Thus, the line break mechanism drivegear train 51 shifts to the next operation regardless of the position ofthe line break lever 50.

The drive gear train reset cam 54 on the line break mechanism drive geartrain 51 is at such an angular phase as to receive a force from thedrive gear train reset lever 52 and the drive gear train reset sub lever53, which are spring-biased. Thus, due to the force from the drive geartrain reset lever 52 and the drive gear train reset sub lever 53, thedrive gear train reset cam 54 is subjected to a rotational force in thecounterclockwise direction in FIGS. 4A to 4H. The line break mechanismdrive gear train 51 keeps operating for as long as this rotational forceacts on the drive gear train cam 54. Also, immediately after reachingthe state of FIG. 4F, the lock member not illustrated in FIGS. 4A to 4H(the arm drive lever A 63 in FIG. 7A) rises, so that the upstreamposition detection sensor 12 starts moving in the +Z direction towardthe retracted position.

FIG. 4G illustrates a next state where the line break legs 13 have movedto the farthest position from the print medium P in the course of theresetting operation of the line break mechanism drive gear train 51. Inthis state, the upstream position detection sensor 12 has moved to theretracted position and is completely separated from the print medium P.FIG. 4H illustrates a subsequent state where the force from the drivegear train reset lever 52 and the drive gear train reset sub lever 53 nolonger acts on the drive gear train reset cam 54 and the line breakmechanism drive gear train 51 has stopped rotating, so that componentshave returned to their initial positions. Specifically, the upstreamposition detection sensor 12 and the line break legs 13 have returned tothe same states as their states in FIG. 4A.

Line break is performed by such a series of operations. It can beobserved that the printing apparatus 1 is actually moved in the periodfrom FIG. 4C to FIG. 4E, as described above. In this period, the heightfrom the print medium P to the body of the printing apparatus 1increases from the height H1 to the height H2 but the downstreamposition detection sensor 11 and the upstream position detection sensor12 remain in contact with the print medium P. Thus, during a line breakoperation, the moving amount of the printing apparatus 1 is detected bythe two sensors, the downstream position detection sensor 11 and theupstream position detection sensor 12.

FIGS. 5A to 5D are views schematically illustrating the positionalrelationship between a printed area PA and the printing apparatus 1 andthe operating state of each sensor in printing operations including linebreak operations. In FIGS. 5A to 5D, each black rectangle represents astate where the upstream position detection sensor 12 or the downstreamposition detection sensor 11 is in contact with the print medium P,while each white rectangle represents a state where the upstreamposition detection sensor 12 or the downstream position detection sensor11 is not in contact with the print medium P. FIG. 5A illustrates astate where a line break operation has been performed after an operationof printing the first line from the right side of FIG. 5A to its leftside, and an operation of printing the second line is being performedfrom the left side toward the right side. In this state, the downstreamposition detection sensor 11 is in contact with the print medium P whilethe upstream position detection sensor 12 is not in contact with theprint medium P.

FIG. 5B illustrates a state where the printing operation of the secondline has been finished, and a line break operation has started.Basically, the line break operation is performed from a positionseparated from the printed area PA. Specifically, after completing theprinting of the second line, the operator continues moving the printingapparatus 1 farther and performs the line break operation from aposition separated from the printed area PA. During the line breakoperation, the downstream position detection sensor 11 is in contactwith the print medium P and the upstream position detection sensor 12 isalso in contact with the print medium P. By performing the line breakoperation from a position separated from the printed area PA asdescribed above, the line break operation can be performed without theupstream position detection sensor 12 rubbed on the printed area PA.

FIG. 5C illustrates a state where the line break operation has beenfinished. In this state, the downstream position detection sensor 11 isin contact with the print medium P while the upstream position detectionsensor 12 is not in contact with the print medium P. FIG. 5D illustratesa state where an operation of printing the third line is being performedfrom the right side toward the left side. In this state, the downstreamposition detection sensor 11 is in contact with the print medium P whilethe upstream position detection sensor 12 is not in contact with theprint medium P. Since the upstream position detection sensor 12 is notin contact with the print medium P, the upstream position detectionsensor 12 is not rubbed on the printed area PA during the printingoperation.

As has been described above, the upstream position detection sensor 12switches back and forth between a contact state and a non-contact state.Hence, a trigger for determining the timing to start a positiondetecting operation is needed. For this reason, in the presentembodiment, the line break leg sensor 208 (see FIG. 3 ) is used. Theline break leg sensor 208 is a sensor that detects the position of theline break legs 13. In the present embodiment, the upstream positiondetection sensor 12 is displaced in conjunction with the line break legs13. Thus, by using the line break leg sensor 208, it is possible todetect whether the upstream position detection sensor 12 is in theraised position or the lowered position. The upstream position detectionsensor 12 is caused to start a reading operation in a case where theline break leg sensor 208 detects that the upstream position detectionsensor 12 is lowered, and is caused to finish the reading operation in acase where the line break leg sensor 208 detects that the upstreamposition detection sensor 12 is raised.

FIGS. 6A and 6B are views illustrating the downstream position detectionsensor 11 and components around it. FIGS. 6A and 6B are views of thedownstream position detection sensor 11 as seen from the positionindicated by the line VI-VI of FIG. 4A. FIG. 6A illustrates a normalstandby state and a printing operation state before the printingapparatus 1 enters a line break operation. The downstream positiondetection sensor 11 is constantly biased toward the print medium P. Inthe state of FIG. 6A, the downstream position detection sensor 11 andthe print medium P are in contact with each other. The guide rollers 10are also in contact with the print medium P. FIG. 6B is across-sectional view illustrating the operating state illustrated inFIG. 4D, which is a state in the middle of a line break operation. InFIGS. 6A and 6B, only the lower unit 2 is illustrated, and a crosssection of the upper unit 3 is omitted.

The Y-direction sensor support shaft 11 d is formed integrally with thedownstream position detection sensor case 11 a and extends in the Ydirection. A downstream sensor case support arm 60 is rotatably engagedwith the Y-direction sensor support shaft 11 d and is rotatablysupported as a link that rotates about a support arm shaft 61 fixed tothe lower unit case 14. In the state of FIG. 6A, the guide rollers 10are in contact with the print medium P and at the same time thedownstream position detection sensor 11 is in contact with the printmedium P, as mentioned above. The downstream position detection sensor11 is brought into contact with the print medium P as a result of thedownstream sensor case support arm 60 being biased by a spring notillustrated with a moment in the clockwise direction in FIG. 6A aboutthe support arm shaft 61.

The downstream sensor case support arm 60 presses the Y-direction sensorsupport shaft lid in the −Z direction, and the two sensor case sliders11 b, which are disposed bilaterally symmetrically about the Y-directionsensor support shaft 11 d, are brought into contact with the printmedium P. As a result, the downstream position detection sensor case 11a is equalized along the print medium P and brought into stable contactwith it. For the sensor case sliders 11 b, it is preferable to use amaterial with a low coefficient of friction with the print medium P.Doing so can reduce the sliding friction between the print medium P andthe sensor case sliders 11 b during printing operations and line breakoperations.

Also, the bearing portion of the support arm shaft 61 and the downstreamsensor case support arm 60 and the bearing portion of the downstreamsensor case support arm 60 and the Y-direction sensor support shaft lidare each preferably configured with as small play as possible.Configurations with small play can prevent a change in the relativepositions of the lower unit case 14 and the downstream positiondetection sensor case 11 a and vibration of the downstream positiondetection sensor case 11 a when the sensor case sliders 11 b receive africtional force. Moreover, the downstream position detection sensorcase 11 a and the downstream sensor case support arm 60 have a springinstalled on one side of a support portion of the downstream positiondetection sensor case 11 a so as to bias the downstream positiondetection sensor case 11 a in one of the ±Y directions. Thisconfiguration can prevent a change in the relative position of thedownstream position detection sensor case 11 a in the line breakdirection and vibration of the downstream position detection sensor case11 a.

Owing to such a support configuration of the downstream positiondetection sensor 11, the downstream position detection sensor case 11 ais stably pressed against the print medium P. Accordingly, the distancebetween the sensor lens 11 c and the downstream position detectionsensor 11, which are fixed inside the downstream position detectionsensor case 11 a, and the print medium P can be maintained constant.Moreover, the distance between the downstream position detection sensor11 and the print medium P can be accurately maintained since theaccuracy of the distance is determined by the dimensional accuracy of asingle component, the downstream position detection sensor case 11 a.

The downstream position detection sensor case 11 a is usually a partproduced by resin molding with a mold. Accordingly, the part'sdimensional reproducibility is high. This makes it possible tosignificantly reduce variation between products. Further, as illustratedin FIG. 1B, the sensor case sliders 11 b are positioned very close tothe sensor lens 11 c. Thus, even if the print medium P is deformed, thesensor case sliders 11 b hold down the deformed portion. Hence, thedownstream position detection sensor 11 is hardly affected by thedeformation of the print medium P and can stably detect the movingamount.

During a line break operation, as illustrated in FIG. 6B, the line breaklegs 13 project from a lower portion of the lower unit case 14 and comeinto contact with the print medium P, so that the body of the printingapparatus 1 moves in the +Z direction. At this time, the downstreamsensor case support arm 60, which is biased in the −Z direction by thespring not illustrated, rotates clockwise and keeps biasing thedownstream position detection sensor case 11 a toward the print mediumP. This makes it possible to continue detecting the moving amount of theprinting apparatus 1 even during the line break operation.

In the present embodiment, the movement of the downstream positiondetection sensor 11 involves a rotational movement via a swingingmovement of the downstream sensor case support arm 60. This means thatthe downstream position detection sensor 11 is slightly displaced in the±X directions as viewed from the lower unit case 14. Nonetheless, theslight displacement in the ±X directions is not problematic since it isonly necessary to compare the position in the Y direction in the stateof FIG. 4C and that in the state of FIG. 4E in order to determine themoving distances and moving directions before and after a line breakoperation.

The configuration of the downstream position detection sensor 11described above is the same as the upstream position detection sensor12. Thus, the above statement also applies to the upstream positiondetection sensor 12.

Next, a reason for retracting the upstream position detection sensor 12to separate it from the print medium P during periods other than whileline break operations are performed in the present embodiment will bedescribed. As has been described above, detecting the position of theprinting apparatus 1 requires the sensor case sliders 11 b and 12 b (seeFIG. 1B) and the print medium P to be rubbed against each other. As canbe analogized from the explanatory views of FIGS. 2C and 2D, if theupstream position detection sensor 12 is brought into contact with theprint medium P during the printing of the second line in FIG. 2D or of asubsequent line, the sensor case sliders 12 b get rubbed on the printedarea PA. If there is an ink yet to be fixed in the rubbed region, thesensor case sliders 12 b spread this ink over the print medium P, whichresults in unintended soiling. This deteriorates the image quality andmust be avoided.

For this reason, in the present embodiment, the upstream positiondetection sensor 12 is separated from the print medium P during printingoperations. During line break operations, which are performed outsidethe printed area PA, rubbing the upstream position detection sensor 12does not cause soiling. The upstream position detection sensor 12 istherefore brought into contact with the print medium P, and the positionof the printing apparatus 1 is detected with the two sensors, thedownstream position detection sensor 11 and the upstream positiondetection sensor 12. This enables accurate measurement of the movingamount of the printing apparatus 1.

FIGS. 7A to 7C are views illustrating the upstream position detectionsensor 12 and components around it. FIGS. 7A to 7C are views of theupstream position detection sensor 12 as seen from the positionindicated by the line VII-VII of FIG. 4A. FIG. 7A illustrates a normalstandby state and a printing operation state before the printingapparatus 1 enters a line break operation. The upstream positiondetection sensor 12 in the present embodiment is configured to bemovable relative to the guide rollers 10 in the ±Z directions, like thedownstream position detection sensor 11.

The upstream position detection sensor 12 is configured to be capable ofbeing moved by a moving mechanism between the retracted position and thecontact position in conjunction with the line break mechanism drive geartrain 51. The moving mechanism includes an upstream sensor case supportarm 62, the arm drive lever A 63, and an arm drive lever B 64. Like thedownstream sensor case support arm 60 (see FIGS. 6A and 6B), theupstream sensor case support arm 62 supports the upstream positiondetection sensor case 12 a. The arm drive lever A 63 is used to drivethe upstream sensor case support arm 62. The arm drive lever B 64 is amember linking the arm drive lever A 63 and the upstream sensor casesupport arm 62.

In the state of FIG. 7A, the upstream position detection sensor 12 hasretracted to the retracted position in conjunction with the line breakmechanism drive gear train 51 and is not in contact with the printmedium P. The upstream position detection sensor 12 is basicallyconfigured to be moved in the ±Z directions by the moving mechanism inconjunction with the line break mechanism drive gear train 51. Theupstream position detection sensor 12 is brought into contact with theprint medium P only during line break operations. During other periods,the upstream position detection sensor 12 is separated from the printmedium P and retracted to the retracted position inside the body of theprinting apparatus 1.

During printing operations, during which the upstream position detectionsensor 12 is located at the retracted position, and in a stateimmediately before starting a line break operation (the state of FIG.7A), a spring not illustrated acts on the arm drive lever A 63 such thatthe arm drive lever A 63 is biased in the +Z direction and brought intocontact with and stopped by a stopper not illustrated. The arm drivelever A 63 includes a protrusion 63 a. The arm drive lever A 63 isengaged with the upstream sensor case support arm 62 via the arm drivelever B 64 fitted to the protrusion 63 a through a hole therein. Theupstream sensor case support arm 62 includes a support arm protrusion 62a, which is pulled up in the +Z direction by the arm drive lever B 64,thereby retracting the upstream position detection sensor 12 to theretracted position inside the printing apparatus 1.

As the line break handle 5 is moved by the operator's operation and aline break operation starts, the cam on the line break mechanism drivegear train 51 acts so as to press the arm drive lever A 63 such that thestate of FIG. 7B is reached from the state of FIG. 7A. Specifically, theprotrusion 63 a of the arm drive lever A 63 moves in the −Z direction,so that the arm drive lever B 64 moves in the −Z direction as well. Thisreleases the support arm protrusion 62 a from a constrained state, sothat the upstream sensor case support arm 62 rotates about the supportarm shaft 61 in the clockwise direction in FIGS. 7A to 7C. Thus, theupstream position detection sensor 12 also contacts the print medium P,as illustrated in FIG. 7B. The protrusion 63 a of the arm drive lever A63 and the hole of the arm drive lever B 64 are fitted to each otherwith a large backlash therebetween. Accordingly, in the state where thearm drive lever A 63 is lowered, the upstream position detection sensor12 is freely movable in the up-down direction within a predeterminedrange. The movement in this state is similar to that of the downstreamposition detection sensor 11 described with reference to FIGS. 6A and6B. FIG. 7C is a view of a state corresponding to FIG. 4D. The rollers10 a and 10 b have been separated from the print medium P but theupstream position detection sensor 12 remains in contact with the printmedium P.

As described above, according to the present embodiment, the positiondetection sensor is configured to be separatable from the print mediumP. Specifically, the upstream position detection sensor 12 situated at aposition where it may slide on a printed area of the print medium P isseparated from the print medium P. Performing a printing operation inthis state can prevent the upstream position detection sensor 12 fromscraping and detaching an ink yet to be fixed and transferring the inkonto another area, and thus suppress deterioration in printing quality.

(Second Embodiment)

In the first embodiment, a description has been given of an example inwhich the downstream position detection sensor 11 and the upstreamposition detection sensor 12 are used to measure the moving amount ofthe printing apparatus 1 during a line break operation. In the presentembodiment, a description will be given of an example in which thedownstream position detection sensor 11 and the upstream positiondetection sensor 12 are used to calculate a change in angle whichoccurred in a movement by a line break operation. The basicconfiguration is similar to the example described in the firstembodiment, and the difference will therefore be described below.

FIG. 8 is a diagram describing an example of calculating a change inangle which occurred in a movement by a line break operation in thepresent embodiment. In FIG. 8 , a position 801 is the position of theprinting apparatus 1 before executing a line break operation. A position802 is the position after executing a line break operation in thedirection of the arrow DY from the position 801. FIG. 8 schematicallyillustrates the posture of the printing apparatus 1 in the course ofperforming this line break operation from the position 801 to theposition 802. Note that the actual amount of movement by the line breakoperation is not as large as illustrated in FIG. 8 . However, if the twopositions overlap, it will be difficult to visually recognize them, andthe moving amount is therefore illustrated in an exaggerated fashion tofacilitate understanding.

In FIG. 8 , the printing apparatus 1 is assumed to be placed on the X-Yplane. An X coordinate and a Y coordinate obtained as a result of theposition measurement by the downstream position detection sensor 11before the line break operation are defined as X1A and Y1A,respectively. An X coordinate and a Y coordinate obtained as a result ofthe position measurement by the upstream position detection sensor 12are defined as X2A and Y2A, respectively. Also, the X coordinate and theY coordinate of the midpoint between the above two sets of coordinatesare defined as XA and YA, respectively. Similarly, an X coordinate and aY coordinate obtained as a result of the position measurement by thedownstream position detection sensor 11 after the line break operationare defined as X1B and Y1B, respectively. An X coordinate and a Ycoordinate obtained as a result of the position measurement by theupstream position detection sensor 12 are defined as X2B and Y2B,respectively. Also, the X coordinate and the Y coordinate of themidpoint between the above two sets of coordinates are defined as XB andYB, respectively.

In the present embodiment, a moving amount L of the sensor midpoint fromthe position 801 to the position 802 in FIG. 8 is calculated. Moreover,an angle 0 of rotation of a line connecting the downstream positiondetection sensor 11 and the upstream position detection sensor 12 frombefore to after the line break operation is calculated. In this way, thechange in the posture of the printing apparatus 1 (the tilt in the X-Yplane) which occurred in the movement by the line break operation can becalculated.

Specifically, the moving amount L and the tilt θ can be represented asbelow via geometric calculations using the coordinates X1A, Y1A, X2A,Y2A, X1B, Y1B, X2B, and Y2B from the sensors' position information.

L=½*((X1B+X2B−X1A−X2A)** 2+(Y1B+Y2B−Y1A−Y2A)** 2)**(½)   (1)

θ=ARCTAN((Y2B−Y1B)/(X2B−X1B))−ARCTAN((Y2A−Y1A)/(X2A−X1A))   (2)

Note that “**” in Equation 1 denotes exponentiation, and “ARCTAN” inEquation 2 denotes arctangent. The moving amount L and the tilt θ arecalculated from the above equations. Thus, in a case of performing aprinting operation after a line break, the print data is corrected byapplying the moving amount L and the tilt θ to the printed area PAbefore the line break. This can reduce misalignment between the printedarea PA and the area to be printed after the line break. The controlunit 16 in the printing apparatus 1 performs the above calculations.Alternatively, the sensors' position information may be sent to anexternal control apparatus, which may in turn perform calculations asshown in Equations 1 and 2. Also, one of the moving amount L or the tiltθ may be calculated.

As described above, according to the present embodiment, it is possibleto calculate a change in the posture of the printing apparatus 1 frombefore to after a line break operation. Accordingly, it is possible tosuppress misalignment between the printed area before the line break andthe area to be printed after the line break.

(Other Embodiments)

In the above embodiments, an example has been described in which, in aline break operation, the user presses down the line break handle 5 inthe moving direction for line break to thereby cause the line breaklever 50 to operate in conjunction with the line break handle 5, and theline break mechanism drive gear train 51 is driven according to theoperation of the line break lever 50 to thereby cause the line breaklegs 13 to operate. However, the line break operation is not limited tothis example. For instance, a motor, a solenoid, or the like that drivesa chain of drives may be used as an actuator. Moreover, the line breakhandle 5 may be replaced with a line break button or the like thatdrives the actuator.

Also, the upstream position detection sensor 12 and the line breakmechanism may be configured as separate components from the body of theprinting apparatus 1. Specifically, in a use situation that requiresaccuracy during a line break movement, a line break device including theupstream position detection sensor 12 and the line break mechanism maybe mounted to the body, and an operation as described in the aboveembodiments may be performed.

Also, in the above embodiments, an example has been described in which asingle position detection sensor is provided on the upstream side andthe downstream side in the moving direction for line break. However, aplurality of position detection sensors may be provided on at least oneof the upstream side or the downstream side.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

According to the present disclosure, it is possible to suppressdeterioration in printing quality.

This application claims the benefit of Japanese Patent Application No.2021-125319, filed Jul. 30, 2021, which is hereby incorporated byreference wherein in its entirety.

What is claimed is:
 1. A printing apparatus comprising: a holding unitconfigured to be held by a user to move the printing apparatus; aprinting unit configured to print an image onto a print medium accordingto a movement of the printing apparatus; a guide unit configured toguide the movement of the printing apparatus; a first detection unitconfigured to detect a relative moving amount between the printingapparatus and the print medium; a second detection unit provided at aposition different from a position of the first detection unit; and adisplacement unit configured to displace the first detection unit from astate where the first detection unit and the second detection unit areboth in contact with the print medium into a state where the firstdetection unit is separated from the print medium.
 2. The printingapparatus according to claim 1, wherein the displacement is performed ina state where a part of the printing apparatus is in contact with theprint medium.
 3. The printing apparatus according to claim 2, whereinthe guide unit is a first guide unit configured to guide movement of theprinting apparatus in a first direction, the printing apparatus furthercomprises a second guide unit configured to guide movement of theprinting apparatus in a second direction crossing the first direction,and the first detection unit is provided on an opposite side of a movingdirection in the second direction relative to the printing unit.
 4. Theprinting apparatus according to claim 3, wherein the part of theprinting apparatus to be in contact with the print medium is the secondguide unit.
 5. The printing apparatus according to claim 3, wherein thefirst detection unit comes into contact with the print medium inconjunction with an operation of moving, in the second direction, theprinting apparatus guided by the second guide unit, and gets separatedfrom the print medium in response to completion of the movement, in thesecond direction, of the printing apparatus guided by the second guideunit.
 6. The printing apparatus according to claim 3, wherein the firstdetection unit is separated from the print medium and the seconddetection unit is in contact with the print medium in a case where theprinting apparatus is moved in the first direction by the first guideunit.
 7. The printing apparatus according to claim 3, further comprisinga calculation unit configured to calculate at least one of a movingamount or a change in a posture of the printing apparatus on the printmedium in a movement of the printing apparatus in the second directionby using a result detected by the first detection unit and a resultdetected by the second detection unit.
 8. The printing apparatusaccording to claim 2, further comprising a sensing unit configured tosense contact of the first detection unit with the print medium.
 9. Theprinting apparatus according to claim 8, wherein after the sensing unitsenses contact of the first detection unit with the print medium, aresult detected by the first detection unit is obtained.
 10. Theprinting apparatus according to claim 1, wherein the displacement unitdisplaces the first detection unit from the state where the firstdetection unit and the second detection unit are both in contact withthe print medium into the state where the first detection unit isseparated from the print medium with the second detection unit kept incontact with the print medium.
 11. A printing apparatus comprising: aholding unit configured to be held by a user to move the printingapparatus; a printing unit configured to print an image onto a printmedium according to a movement of the printing apparatus; a guide unitconfigured to guide the movement of the printing apparatus; and a seconddetection unit configured to detect a relative moving amount between theprinting apparatus and the print medium; and a first detection unitconfigured to detect a relative moving amount between the printingapparatus and the print medium and configured to be able to change adistance between the first detection unit and the print medium withoutchanging a distance between the second detection unit and the printmedium.
 12. The printing apparatus according to claim 11, wherein thedistance between the first detection unit and the print medium ischanged in a state where a part of the printing apparatus is in contactwith the print medium.
 13. The printing apparatus according to claim 12,wherein the guide unit is a first guide unit configured to guidemovement of the printing apparatus in a first direction, the printingapparatus further comprises a second guide unit configured to guidemovement of the printing apparatus in a second direction crossing thefirst direction, and the first detection unit is provided on an oppositeside of a moving direction in the second direction relative to theprinting unit.
 14. The printing apparatus according to claim 13, whereinthe part of the printing apparatus to be in contact with the printmedium is the second guide unit.
 15. The printing apparatus according toclaim 13, wherein the distance between the first detection unit and theprint medium is changed to a first distance in conjunction with anoperation of moving, in the second direction, the printing apparatusguided by the second guide unit, and is changed to a second distancelonger than the first distance in response to completion of themovement, in the second direction, of the printing apparatus guided bythe second guide unit.
 16. The printing apparatus according to claim 15,wherein the distance between the first detection unit and the printmedium is the second distance and the distance between the seconddetection unit and the print medium is the first distance in a casewhere the printing apparatus is moved in the first direction by thefirst guide unit.
 17. The printing apparatus according to claim 3,wherein the printing unit has a nozzle array being a plurality ofnozzles arranged side by side, and the second direction corresponds to adirection in which the nozzle array is arranged.
 18. The printingapparatus according to claim 12, wherein the printing unit has a nozzlearray being a plurality of nozzles arranged side by side, and the seconddirection corresponds to a direction in which the nozzle array isarranged.